#00062155

A 42-year-old HIV-positive woman presented with lymphadenopathy, fever, weight loss, and splenomegaly. The patient underwent excisional biopsy of an enlarged cervical lymph node, which showed regressed, partially hyalinized follicles with prominent, intruding mantle zones with a concentric, onion skinning pattern of lymphocytes and penetrating vessels characteristic of Castleman disease (A). Within the expanded mantle zones and nearby interfollicular regions are scattered medium to large-sized plasmablastic cells with amphophilic cytoplasm and vesicular nuclei with one to two prominent nucleoli. These CD20+ plasmablastic cells (B) show strong, stippled nuclear staining for Kaposi sarcoma-associated herpesvirus (KSHV, also known as HHV-8, C), strong cytoplasmic IgM expression (D), and show lambda light chain restriction (E) compared to kappa light chain (F). Collectively, these features are characteristic of HHV-8 positive multicentric Castleman disease, often seen in immunocompromised patients secondary to HIV infection.